JP2776814B2 - Malfunction prevention device for NC device - Google Patents

Description

The present invention relates to a device for preventing a malfunction of an NC device of an NC machine tool controlled and operated by the NC device, and in particular, to a high-precision such as a double tail machining of a turbine rotor. The present invention relates to an NC processing failure prevention device suitable for NC processing that requires the following. [Prior Art] As described in Japanese Patent Application Laid-Open No. 57-102732, a conventional apparatus detects an abnormality by an electric conduction state between a cutting tool (knife) and a material to be cut (work). The detection method is adopted. [Problems to be Solved by the Invention] The above-mentioned prior art is characterized in that the safety device operates only when the cutting tool and the material to be cut have an abnormality during processing and are separated from each other. No consideration is given to the fact that the workpiece moves into the work to be cut into the workpiece and deviates from the set operation, and there is a problem that an abnormality in this case cannot be detected. SUMMARY OF THE INVENTION An object of the present invention is to detect an abnormality in which a cutting tool bites into a work and cannot be reworked, detects the abnormality, and stops the NC device to prevent a machining defect. [Means for Solving the Problems] The object is to provide a cutting tool for cutting a workpiece, a tool rest on which the cutting tool is fixed, and moving the tool in X and Y directions, and one end attached to the tool rest. The other end is provided with an arm to which a contact is attached via an insulating material for electrical insulation, a gauge machined to the shape and dimensions to be machined, and a fixing bracket made of an insulating material. A table fixed through the contact, the contact and the gauge are provided with a predetermined gap, and a power supply device for applying a voltage between the contact and the gauge, and a flow when the contact and the gauge come into contact with each other Providing a detection device for detecting the current, having a signal output device that receives the current obtained by the detection device, generates a stop command to the NC device as an NC abnormality, and an external display device that externally displays the abnormality. By being It is made. [Operation] The arm attached to the portion supporting the cutting tool (blade) and the contactor mounted electrically insulated from the arm perform the same movement as the blade. In addition, the gauge corresponding to the processing dimension fixed electrically insulated at a place unrelated to the movement of the blade does not move. When the NC operation is performed, the contact moves along the shape of the gauge. Therefore, if a gap of the processing tolerance is provided between the two, the contact does not normally contact. Therefore,
At the time of contact, it means that the blade has exceeded the tolerance and has cut into the work. Therefore, an NC stop command is output and the NC device is stopped, so that malfunction can be prevented. [Embodiment] One embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3. FIG. FIG. 1 shows an outline of a case in which an apparatus for preventing malfunction of an NC device according to an embodiment of the present invention is used for lathe processing of a dovetail portion of a turbine rotor. The turbine rotor has a shape with multiple disks attached to the shaft,
The dovetail performs a stepping process of implanting a blade on a disk. The work 1 shows its cross section, and the cutting tool 2
Is fixed to the tool post 3, and the tool post 3 is moved in the X and Y directions in the drawing to perform machining. In order to take out the movement of the blade, the arm 4 is attached to the tool post 3, and a pin-shaped contact 6 is provided at an end of the arm 4 via an insulating material 7 for electrically insulating the blade 4.
Is attached. Reference numeral 5 denotes a gauge machined to the shape and size to be machined. In a normal machining state, the contact moves along the contour of the gauge according to the movement of the cutting tool. FIG. 2 is a view taken in the direction of the arrow II in FIG. 1, and the gauge is shown in cross section. The gauge 5 is fixed on the table 8 with a fixing jig made of a material that does not conduct electricity for electrical insulation. The table 8 is attached to an immovable place 10 irrespective of the movement (X, Y directions) of the tool rest 3. The gauge 5 and the contact 6 are set by giving a certain gap C, and the size is set to the minimum allowable even if the cutting tool bites, that is, the maximum value of the processing tolerance. Usually, it is about 0.1 mm. When the contact 6 comes into contact with the gauge 5 beyond the gap, it is determined that the contact 6 is abnormal. The control function of the present invention will be described with reference to FIG. Control device
11 checks the continuity with the power supply unit 12 for applying electricity between the contact 6 and the gauge 5, outputs a stop command to the NC device 14 upon contact, and further outputs a display signal to the external display device 15 such as a lamp or a buzzer. And an output unit 13. When an error occurs due to malfunction of the NC device and the cutting tool 2 bites into the work 1 beyond the tolerance, the contact 6
During this time, the state becomes conductive, a stop command is output from the output unit 13 to the NC device 14, and the machine stops and processing stops. This has the effect of preventing the occurrence of processing defects due to malfunction of the NC device. [Effects of the Invention] According to the present invention, it is possible to prevent a cutting tool from digging into a work due to a malfunction of an NC device, so that it is possible to prevent occurrence of uncorrectable machining failure due to excessive cutting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an outline of an embodiment of the present invention, FIG. 2 is a view taken in the direction of arrow II in FIG. 1, and FIG. 3 is a block diagram showing electrical connections. is there. 1 Workpiece 2 Cutting tool 3 Tool post 4
arm.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23Q 17/00 B23Q 11/00

Claims (1)

(57) [Claims] An apparatus for preventing malfunction of an NC machine tool controlled and operated by an NC apparatus, comprising: a cutting tool for cutting a workpiece; a tool rest on which the cutting tool is fixed, and the tool moving the tool in X and Y directions; An arm having one end attached to the base and a contact attached to the other end via an insulating material for electrical insulation, a gauge machined to the shape and dimensions to be machined, and the gauge is made of an insulating material. A table fixed via a fixing fixture is provided, the contact and the gauge are installed with a predetermined gap, and a power supply device for applying a voltage between the contact and the gauge, and the contact and the gauge are A signal output device for detecting a current flowing when contact is provided, receiving a current obtained by the detection device, and causing the NC device to generate a stop command as an NC abnormality, and an external display for externally displaying the abnormality Malfunction prevention apparatus of the NC apparatus characterized by and a location.